I agree that would be preferred. However, all of their laptops have had Windows on them before (as far as I can tell). So you are contributing to demand for used ThinkPads when you buy them, and thus increasing the value of new Windows-running ThinkPads (because they have higher resale value if more people want to buy them used). I'd rather stay out of the Windows ecosystem altogether.

When someone is selling their ThinkPad, neither Lenovo nor Microsoft are part of that transaction so I fail to see any problem. Seems a poor argument to advance the sales of computers that are less free.

Resale value only makes sense for products that people expect to resell when they buy them. I don't think laptops are in that category, so I don't think we need to consider that factor when buying second-hand laptops. Buy the hardware that is possible to run all-free software on.